Storage battery positive electrode



Patented Nov. 8, 1938 UNITED STATES STORAGE BATTERY POSITIVE ELECTRODEAND METHOD OF MAKING SAME Harold R. Harner, Frederick H. Schultz, andEverett J. Ritchie, Joplin,

Mo., assignors to The Eagle-Picher Lead Company, Cincinnati, Ohio, acorporation of Ohio 7 No Drawing. Original application September 30,

1935, Serial No. 42,878

, now Patent No.

dated February 15, 1938. Divided and this application January 13, 1938,Serial No. 184,844

6 Claims.

Our invention relates to lead-acid storage batteries and moreparticularly to the positive plates or electrodes. By our invention weproduce electrodes of far greater tenacity and consequently greater lifethan ordinary electrodes, and fur- The common cause of failure of thepositive plates or electrodes in service is due to the poor particles oflead peroxide composing the electrode. This bond is usually onlyresidual lead sulfate and is not tenacious enough to prevent rapiddisintegration of the electrode during use. The gassing at the endbuckle in undercharge service due to the density of the material notallowing suflicient pore space or porosity to take up the volumeincrease as the active material changes from lead peroxide to leadsulfate on complete discharge. vention we eliminate all theseundesirable features and provide a positive electrode of low aplow costwith at the same time high porosity, little tendency to buckle and withmarkedly improved life characteristics.

In carrying out phenol and formaldehyde into the active material ormaterial to be made active and set or condense these chemicals bydipping the electrode into dilute take the unformed positive electrodesas they come from the drier after pasting, dip the eke electrode. Theabove is by way of example only and we "may depart from it widely inprocessing as needed by the particular electrode in question withoutdeparting from the spirltof the invention. We may, for example, preferto dip the acid. For example, we may electrode in a water solution ofphenol or any other well known solvent and set the ,bond by forming theelectrode in an electrolyte of dilute sulfuric acid and formaldehyde. Ineither case a bonding network of phenol-formaldehyde condensationproduct isformed, mainly on the surface of theelectrode but extendinginto the pores thereof and partially enclosing the already existingnetwork of lead compounds present in the electrode. This network ofphenol-formaldehyde condensation product is relatively stable in batteryelectrolyte and serves to extend the useful life very greatly, doublethe life from untreated plates having been shown on laboratory tests.

The bonding network of phenol-farmaldehyde condensation product set upin the electrode on treating is independent of the original compositionof the electrode. The paste from which the electrode is made may containas ingredients red lead, litharge, lead sulphate, lead suboxide, leadpowder or mixtures thereof together with such fillers or addition agentsas may have been incorporated. Once the paste has been filled into thegrids and the resulting electrode dried there is produced a substantialstructure of lead materials. Our bonding network is produced in thevoids within and on the surface of this lead structure independently ofthe original character or composition of the paste ingredients.

By way of illustration we may prepare a positive plate by an admixtureof red lead, litharge and lead powder to which is added dilute sulfuricacid to produce the desired paste density; this is pasted into the gridby any suitabl means and may then be treated in our solutio or we mayfirst dry the plate before treating. Vtle prefer to use the dried plateswherein the lea network has been firmly established by propertdrying.From the known density of the paste ii'sedit is a simple matter tocalculate the volume of liquid required to fill the pores of the dry'pate. We prefer to adjust our solution to sue a strength that the volumeof our solutions absorbed per plate will carryinto the plate apredetermined amount of phenol and formaldehyde.

For example, to treat plates carrying 150 grams of dry active material,and having a porosity of 7 l5 cubic centimeters, to introduce 1% ofphenolformaldehyde bonding material in the plate, we so adjust oursolutions that each l5 cubic centimeters contains 1.5 aldehyde combined.Inasmuch as 'phenol and formaldehyde set or condense indifferent ratiosproducing diflerent products, we may desire tograms of phenol and form--2 vary the ratio of one to the other in our solutions to produce theresult desired in the case in question. For example we have used thephenol and formaldehyde in the ratios of their molar weights with goodresults. To make such a solution to the strength needed 'above we wouldadd 60.5 grams of 88% phenol and 42.3 grams of 40% formaldehyde to eachliter of water solution desired. As our second, or setting solution weuse dilute sulfuric acid, 1,100 sp. gr. for example. Following thistreatment we prefer to dry the plate thoroughly before the further stepof forming the plate.

This application is a division of our co-pending application Serial No.42,878 filed September 30, 1935 now Patent No. 2,108,748 granted Feb.15, 1938. 4

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent, is:

1. Method of producing a lead acid storage battery electrode whichcomprises introducing active material into the interstices of the grid,introducing into the active material a solution of phenol and formingthe electrode in a solution of dilute sulphuric acid and formaldehyde.

2. Method of producing a bonding network for active material in a leadacid storage battery electrode which comprises treating the pasted gridwith a solution of phenol and forming the electrode in a solution ofdilute sulphuric acid and formaldehyde.

3. Method of preparing a lead acid storage battery electrode whichcomprises adding 60.5 grams of 88% phenol to each liter of solutiondesired and immersing the unformed electrode in the solution, removingthe electrode and immersing in a solution of sulphuric acid andformaldehyde equal to 42.3 grams of 40% formaldehyde equal to each literof solution.

4. A lead acid storage battery electrode the paste ingredients of whichhave been treated with a solution of phenol and a subsequent treatmentwith dilute sulphuric acid and formaldehyde to produce on formation thebonding network.

5. A lead acid storage battery electrode comprising as ingredients oneor more oxides of lead selected from the group consisting of litharge,v

red lead, lead sulphate, and lead suboxide, which has been treated witha liquid solution of phenol and then with dilute sulphuric acid andformaldehyde to form a bonding network.

6. A lead acid storage battery electrode characterized by the presenceof a bonding network produced in situ by treating the active ingredientswith a solution of phenol and forming the electrode in a solution ofdilute sulphuric acid and formaldehyde.

HAROLD R. HARN'ER. FREDERICK H. SCHULTZ. EVERETT J. RITCHIE.

